Cause of Hearing Loss - Congenital Cytomegalovirus

May Be Responsible for Some Unknowns

What is CMV?

CMV is an abbreviation for cytomegalovirus. If a mother gets a CMV infection for the first time in her life while pregnant, it can be passed to the fetus during birth. Most pregnant women will not have any symptoms, and those that do have symptoms experience something similar to mononucleosis. Fortunately, according to the Centers for Disease Control and Prevention (CDC), only a small percentage (1% to 4%) of uninfected pregnant women will become infected with CMV.

At birth, the newborn may not have any symptoms. If it does, the symptoms usually include jaundice or an enlarged liver or spleen. As the baby grows, the damage caused by the CMV becomes evident -- mental and physical disabilities (including hearing loss) appear.

A substantial percentage of symptomatic newborns and a smaller percentage of nonsymptomatic newborns will develop hearing loss, which usually is progressive hearing loss.

According to the CDC, almost 90 percent of Americans get the CMV infection before age 40. Most people who get it after they are born have no symptoms. Or if they do, they are generally mild or similar to mononucleosis. It is usually transmitted through intimate contact with body fluids like saliva.

Preventing CMV Transmission

There is no vaccine for CMV at this time. The only known way to prevent CMV transmission is by frequently washing your hands. This may help prevent transmission to a pregnant woman who has contact with a dirty diaper or a young child in a day-care center.

How a CMV Infection is Diagnosed

If you have a child with an unknown source of hearing loss, it may be possible to determine if the cause was CMV. Laboratory tests can check for the presence of CMV antibodies and viral culture.

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